This invention relates to a sectional frame for forming variously sized shielding units for filtering the radiation emitted by apparatus incorporating video terminals.
The use of apparatus provided with visual display units or video terminals is known to be continuously increasing in the most diverse industrial sectors.
It is also known that during operation, such terminals emit radiation and suffer from variable or pulsating brightness, which besides bothering the operator can inflict irreversible damage in the long term.
To at least partly remedy the aforesaid problems, shielding devices have been proposed comprising a stratified glass plate to be placed in front of the screen of said visual display units or video terminals, in order to filter said radiation and/or attenuate said brightness variations.
Two examples of said known devices are well illustrated and described in Italian model applications Nos. 34876 B/89 and 34825 B/90, to which reference should be made for further details.
Basically, the known devices of the cited documents comprise a flat structure to be removably fixed to the upper face of the housing of a visual display unit or video terminal, to support a frame containing a shielding plate performing the aforesaid function.
Specifically, said frame comprises two flat annular elements, namely a front and a rear, which can be snap-fitted together to simultaneously clamp and centre the shielding plate.
Said flat annular elements are produced by moulding a convenient synthetic material, and each consists of a one-piece structure, the inner dimensions of which conform to the outer dimensions of the screen with which the shielding plate is to be associated.
However, commercially available visual display units or video terminals comprise a wide range of standard screen sizes, with the result that different frames must be available in a number equal to the number of different screen sizes.
This is particularly inconvenient for the frame manufacturer, considering that starting from a frame (for example a square frame) with inner dimensions of for example 25.times.25 inches and terminating with a frame (for example a square frame) with inner dimensions of for example 10.times.10 inches, it may be necessary to provide the whole range of frames decreasing in one inch steps (both in height and width) from the largest downwards.
In addition, rectangular frames may be required, with their major axis lying horizontally or vertically.
It is immediately apparent that such a production range involves problems of study/design, manufacture (such as the preparation of costly moulds correspondingly equipped and sized), packaging/storing and distribution/advertising.